Reconsideration of the theoretical supplementation of decay data in fission product decay heat summation calculations (II)

In our previous paper, the theoretical overcorrection in JENDL FP Decay Data File 2000 for the decay heat summation calculation was suggested. In order to eliminate this, we redefined the criteria of applying the theoretical values to average energy release per decay, that is, E_β and E _γ values. Furthermore, the results of the TAGS (total absorption gamma ray spectrometer) measurements up to the newest ones are adopted into the decay heat calculations. As a result, we obtained a reasonable agreement between the calculation and the sample irradiation experiments, not only for ²³⁹Pu but for ^233;235;238U and ²⁴¹Pu. The present revision of the FP decay data file will provide us with a reasonable starting point for the future revision of the decay data file by introducing the results from the TAGS effort now in progress. In addition, the effects of the so-called pandemonium problem are clearly demonstrated and this also affects the conventional decay schemes, especially for the short-lived FP nuclides having large _β-decay Q_β- values.